In a large number of sporting goods and industrial applications, the article of interest must be strong, wear resistant, lightweight and display high resilience, high flexural stiffness at room temperature as well as elevated temperature (e.g. up 200° C.) while having been manufactured by a convenient and cost-effective method.
Harmala in U.S. Pat. No. 5,320,386 (1994) describes a lightweight, high strength, composite titanium ski pole. The composite shaft includes a hollow first shaft of a titanium alloy and a hollow second shaft of stiffening material. The first and second shafts are assembled to have the exterior surface of one of the shafts in surface-to-surface contact with an interior surface of the other one. By employing the stiffening tube in conjunction with the titanium alloy tube, the titanium alloy tube is still permitted to bend, but is substantially prohibited from bending in an amount which would approach its yield point and result in permanent deformation.
Sandman in U.S. Pat. No. 5,538,769 (1969) describes a graphite composite shaft with a reinforced tip, suitable for use in fishing rods or golf clubs. The shaft includes a base shaft made at least partially of graphite composite material provided in one or more layers or plies. These shafts have relatively slender tips that are normally prone to impact damage.
Fishing rod tip failure/breakage is a major cause of warranty returns of fishing rods to the manufacturer. In addition, as golf clubs are swung in close proximity to the ground, it is not unusual for the club head to strike the ground with considerable force, applying a large force or torque to the narrowest portion of the shaft, i.e. to the tip of the shaft that is joined to the club head. This impact can cause failure of the composite shaft at this point, causing the tip of the shaft to break at or closely adjacent the club head. The reinforcement layer described in this patent, which extends only part of the way up the length of the base shaft, is intended to render the shaft more resistant to impacts occurring at the tip and increase the durability of the shaft without decreasing the performance of the fishing rod or golf club that incorporates the shaft.
Perryman in U.S. Pat. No. 6,354,960 (2002) describes a golf club shaft with controllable feel and balance using a combination of fiber-reinforced plastics and metal-coated fiber-reinforced plastics to obtain an individually optimized golf club. A filament-wound outer layer having at least one ply including metal-coated fibers covers a sheet-rolled or filament-wound core. The fibers can be metal-coated with metals such as nickel, titanium, platinum, zinc, copper, brass, tungsten, cobalt, gold or silver. The use of metal-coated fibers permits the use of combinations of fiber reinforced plastic and metal-coated fibers in producing golf shafts with optimum performance properties. Specific placement of the metal-coated fibers makes it possible to add weight to predetermined points in the shaft in order to shift the flex and balance points without varying the torsional properties of the shaft and to provide the optimum flex for a given golf club design.
Yanagioka in U.S. Pat. No. 4,188,032 (1980) discloses a nickel-plated golf club shaft made of fiber-reinforced material having on substantially its entire outer surface a metallic plating selected from the group consisting of nickel and nickel based alloys for the purpose of providing a wear-resistant coating. The electroless nickel coating of choice is 20 μm thick and the deposition time is 20 hrs, resulting in a deposition rate of 1 μm/hr.
Kim in U.S. Pat. No. 4,951,953 (1990) describes a golf club electroless coated with a high Young's Modulus material (≧50 million psi) or with a composite material having a high Young's Modulus material as a substantial ingredient in the matrix. Diamond is particularly preferred as a coating or coating component due to its high strength and relatively low density. The coating may be applied, for example, using an electroless “composite diamond coating” technique, to either the head or shaft of the club, the club head only or the shaft only to provide improved directional accuracy and impact performance characteristics. The coating is typically applied using an electroless “composite diamond coating” technique, to either only the striking face of the club head or, preferably, to a substantial portion of the shaft below the grip and over the club head continuously over the junction between the shaft and club head. The coating thickness ranges from about 1 to 2 mils (25 μm to 50 μm), although 1-10 mil (25 μm to 250 μm) thick coatings are noted and the particle size of the coating material is from about 0.1 μm to 50 μm with a preferred range of 1 μm to 10 μm.
Chappel in U.S. Pat. No. 6,346,052 (2002) discloses golf club irons with multilayer construction. The golf club head comprises a soft nickel alloy core and a hard chrome coating. The process used to produce the golf club heads involves an investment casting process in which the soft nickel alloy core is cast and the hard chrome coating is electroplated onto the core. This multilayer design produces a golf club iron that is durable and consistent from iron to iron with feel characteristics which are generally equal to or better than traditional clubs formed from forged mild carbon steel. Unlike the decorative chrome used on prior art golf clubs (hardness of about 35 to 45 Rockwell C, typical thickness between 0.05 to 0.2 mil) the chrome outer layer used in the invention is between 0.8 mils to about 1 mil (20 μm to 25 μm) thick, which is at least four times thicker than conventional applications of decorative chrome in prior art clubs. The hard chrome plating employed is asserted to provide durability without compromising the superior feel characteristics of the relatively soft nickel alloy core when a golf ball is struck.
Takeda in U.S. Pat. No. 5,935,018 (1999) describes a golf club and method of manufacturing intended to prevent copper or copper alloy material used in the head from corroding. The invention also aims at preventing galvanic corrosion when combining such materials with other materials, such as aluminum alloys, by applying a nickel-plated coating layer to the head, followed by chrome plating.
Umlauft in U.S. Pat. No. 6,106,417 (2000) describes a lightweight tennis racket with a high stiffness. The racket is formed from a composite material including carbon fibers, titanium fibers, and epoxy resin and is at least 27 inches long, weighs less than 9.2 ounces when strung, and has a frequency of vibration of the first mode of bending under free-free constraint of at least 175 Hz. To achieve the lightweight, high strength properties, the carbon-reinforced composite is strengthened particularly in the racket throat area with metallic titanium fibers.
Numerous publications describe sport racquets reinforced and stiffened by structural straps or plates at the outer or inner surfaces, or within the wall of the handle and frame, including Stauffer (U.S. Pat. No. 3,949,988 (1976), Matsuoka in JP2000061005 (1998) and JP09285569 (1996).
Reed in U.S. Pat. No. 5,655,981 (1997) describes a shaft for a hockey stick comprising a non-metallic elongated material member; a first layer comprised of a resilient yet tough material bonded to the member; a second layer comprised of metal applied to the first layer by a metal deposition process; and a third layer comprised of a clear, resilient, tough material encasing said second layer of metal. The thin metallic layer is applied to the substrate by a vapor vacuum deposition process. The base layer, metallic layer and top layer have an overall thickness of less than approximately 3 mil. The purpose of the thin metallic layer applied to a non-metallic shaft, having a maximum thickness of 0.01 mil (0.25 μm), is entirely to enhance the appearance and the metals of choice include aluminum, copper, gold and silver.
Burns in U.S. Pat. No. 4,124,208 (1978) discloses a durable, lightweight hockey stick having opposed metal outer skins made of a single piece including the shaft and integral handle and blade portions with a metal honeycomb sandwiched there between. The metal hockey stick provides long life at an overall weight similar to that of wood and is relatively inexpensive.
Erb in U.S. Pat. Nos. 5,352,266 (1994), and 5,433,797 (1995) describes a process for producing nanocrystalline materials, particularly nanocrystalline nickel. The nanocrystalline material is electrodeposited onto the cathode in an aqueous acidic electrolytic cell by application of a pulsed DC current. The cell also optionally contains stress relievers. Products of the invention include wear resistant coatings, and magnetic materials.
Palumbo WO2004/001100 A1 (2002) discloses a process for forming coatings or freestanding deposits of nanocrystalline metals, metal alloys or metal matrix composites. The process employs drum plating or selective plating processes involving pulse electrodeposition and optionally a non-stationary anode or cathode, Novel nanocrystalline metal matrix composites are disclosed as well. Also described is a process for forming micro-components with grain sizes below 1,000 nm.
Although a number of electrolytic and electroless plating processes are known to provide metallic coatings to the surfaces of various articles such as golf club heads, shafts and the like, heretofore the electrodeposited metallic coatings used are thin (limited typically to less than 25 μm) and applied primarily for scratch and corrosion resistance.
Electroless coating deposition rates are low, typically 0.25 mil/hr (6.25 μm/hr) to 0.5 mil/hr (12.5 μm/hr) whereas galvanic coating deposition rates typically exceed 1 mil/hr (25 μm/hr). The typical coating thickness values for electroless plating processes are less than 1 mil (25 μm). In the case of electrolytic coatings it is well known that after the coating has been built up to a thickness of about 5-10 μm, it tends to become highly textured and grows in a fashion whereby anisotropic and elongated columnar grains prevail with typical grain widths of a few microns and grain lengths of tens of microns. Prior art thin coatings applied by electroless or conventional electroplating processes exhibit amorphous or conventional grain size values (≧5 μm) and do not significantly improve the overall mechanical properties of the coated article.
Substantial grain size reduction has been found to strongly enhance selected physical, chemical and mechanical properties of a coating. For example, in the case of nickel, the ultimate tensile strength increases from 400 MPa (for conventional grain-sizes greater than 5 μm) to 1,000 MPa (grain size of 100 nm) and ultimately to over 2,000 MPa (grain size 10 nm). Similarly, the hardness for nickel increases from 140 VHN (for conventional grain-sizes greater than 5 μm) to 300 VHN (grain size of 100 nm) and ultimately to 600 VHN (grain size 10 nm) We therefore expected that the application of coatings of this kind could improve the durability and performance characteristics of structural components of sporting equipment and other equipment or parts requiring strong, ductile and lightweight components.